Lounge Doctors - Nutritionists etc

TLDR How efficient is a NORMAL HEALTHY MAMALS digestive tract?

(for the sake of simplicity we will use 1 common calorie which is in reality equal to 1 kilo calorie because that is how food products are labeled… (for those that don't know, the calories on your food labels should be multiplied by 1k to get the REAL calorie count))




So I am wondering how efficient the digestive tract is at extracting calories. If i eat a 1000 calorie candy bar, assuming nothing is wrong with my digestive tract, how many calories will my body actually extract from it?


Its my understanding that they determine calories by burning the food, and fire tends to be 100% efficient, but when i eat nuts, corn, lettuce, etc i often poop out some "undigested" pieces of food. Are those calories that were wasted by my body?


Do my body elect to be more efficient or less efficient with the "fuel" i put in it depending on how much demand my body things there is for calories? Could my body elect to not digest an entire meal if it wanted to?

Quote from HeyLookItsMe : TLDR How efficient is a NORMAL HEALTHY MAMALS digestive tract? (for the sake of simplicity we will use 1 common calorie which is in reality equal to 1 kilo calorie because that is how food products are labeled… (for those that don't know, the calories on your food labels should be multiplied by 1k to get the REAL calorie count)) So I am wondering how efficient the digestive tract is at extracting calories. If i eat a 1000 calorie candy bar, assuming nothing is wrong with my digestive tract, how many calories will my body actually extract from it? Its my understanding that they determine calories by burning the food, and fire tends to be 100% efficient, but when i eat nuts, corn, lettuce, etc i often poop out some "undigested" pieces of food. Are those calories that were wasted by my body? Do my body elect to be more efficient or less efficient with the "fuel" i put in it depending on how much demand my body things there is for calories? Could my body elect to not digest an entire meal if it wanted to?

Undigested waste is just that, undigested waste. The body couldn't use it so it passed through the digestive tract and out. That's not so bad as it is not loggjammed within your lower intestines and backed up.

The fuel process is done within your stomach and small intestine. The food is broken down and nutrients and sugars are absorbed into the blood stream, turned to glucose and then to glycogen, then the body uses it as fuel. Insulin is introduced into the blood stream to maintain and regulate blood sugar levels and the remainder is stored as fat if not properly used. The gall bladder injects extra enzymes to break down food and fats, and then the pancreas does its part in the digestion process by breaking down the big 3 even more in the intestines before the remainder gets excreted. If it is excreted, it wasn't used.

Some foods break down and are digested far more than others. Nuts and corn shells are notorious examples.

Quote from menace33 : Undigested waste is just that, undigested waste. The body couldn't use it so it passed through the digestive tract and out. That's not so bad as it is not loggjammed within your lower intestines and backed up. The fuel process is done within your stomach and small intestine. The food is broken down and nutrients and sugars are absorbed into the blood stream, turned to glucose and then to glycogen, then the body uses it as fuel. Insulin is introduced into the blood stream to maintain and regulate blood sugar levels and the remainder is stored as fat if not properly used. The gall bladder injects extra enzymes to break down food and fats, and then the pancreas does its part in the digestion process by breaking down the big 3 even more in the intestines before the remainder gets excreted. If it is excreted, it wasn't used. Some foods break down and are digested far more than others. Nuts and corn shells are notorious examples.

yes, this i know, i didn't ask HOW food is digested, i asked how efficient the digestion process is and if the body can alter that efficiency

so the question still remains, does poop have calories and if so is it because

• the body CHOSE not to digest the food (the body says I'm fat i don't need to intake more calories right now)
• because the body didn't have time to (too much food too little intestine)
• the body couldn't (some foods can't be digested)

In other words, if you eat 1000 calories how many calories does your body end up actually getting?

I wonder how many calories this poop has?

Steak made from human poop passes taste test

http://www.mnn.com/green-tech/res...taste-test

Quote from HeyLookItsMe : yes, this i know, i didn't ask HOW food is digested, i asked how efficient the digestion process is and if the body can alter that efficiency so the question still remains, does poop have calories and if so is it because the body CHOSE not to digest the food (the body says I'm fat i don't need to intake more calories right now) because the body didn't have time to (too much food too little intestine) the body couldn't (some foods can't be digested) In other words, if you eat 1000 calories how many calories does your body end up actually getting?

Well you know a calorie is a unit of energy. The only way poop is going to have calories is if you consume it, reintroduce it back into the body, and then see how the body uses it for energy.

Once excreted, the only calories burned from the waste was in the excretion process.

You are asking the wrong question. Your body will burn as much calories as it needs to do what you want your body to do. If you don't do jack and consume this food and that food then it's not going to have a need to burn off 1000 cal for the energy it needs. The rest is stored as fat or waste.

So I ask you, in that 1000 cal consumed, how much activity are you putting in?

My guess would be that the human digestive system is 50-75% effective at extracting the nutrients from eaten food. It depends on what you eat. If it's fiber or dairy, your body may not be able to process it.

The only thing I know about is bacon. Eighty-five percent of the calories in bacon is in the fat that is drained off. You can eliminate another 10% by putting the cooked bacon on something to absorb the remaining liquid fat from the slices. At that point bacon can pretty much be considered calorie-free.

This thread is full of TMI.

Quote from tigerstar : this thread is full of shit.

ftfy...

Quote from Iaaaiws : The only thing I know about is bacon. Eighty-five percent of the calories in bacon is in the fat that is drained off. You can eliminate another 10% by putting the cooked bacon on something to absorb the remaining liquid fat from the slices. At that point bacon can pretty much be considered calorie-free.

mmmmmmmmmm bacon!

Quote from menace33 : You are asking the wrong question. Your body will burn as much calories as it needs to do what you want your body to do. If you don't do jack and consume this food and that food then it's not going to have a need to burn off 1000 cal for the energy it needs. The rest is stored as fat or waste. So I ask you, in that 1000 cal consumed, how much activity are you putting in?

IM NOT TALKING ABOUT ACTIVITY and I AM asking the right question


I'm simply asking if you eat 1000 calories how many calories end up being available to your body… i don't care what the body does with it… thats not the point… I'm trying to understand how efficient the body is at getting the caloric potential from a food source….

Quote from HeyLookItsMe : IM NOT TALKING ABOUT ACTIVITY and I AM asking the right question I'm simply asking if you eat 1000 calories how many calories end up being available to your body… i don't care what the body does with it… thats not the point… I'm trying to understand how efficient the body is at getting the caloric potential from a food source….

Calories are units of energy. How efficient will depend on how active you are, will depend on factors such as BMI, muscle mass ratio, thyroid, pituitary, and adrenal function. Genetics play a part in it also. Bottom line there is no definitive answer.

I'll use Michael Phelps for example. How he burned 1000 calories consumed when he was in Beijing was probably a little different than when he was in London. When he's done swimming casually in retirement, how he burns calories will be different then when he was training 6 days a week. When he's 35 it'll change even more. When he's 50, as the body changes like those factors mentioned above change with age, it'll be different yet and still.

There is no definitive answer on how the body efficiently will burn a set # of calories at any one given time.

Quote from menace33 : Calories are units of energy. How efficient will depend on how active you are, will depend on factors such as BMI, muscle mass ratio, thyroid, pituitary, and adrenal function. Genetics play a part in it also. Bottom line there is no definitive answer. I'll use Michael Phelps for example. How he burned 1000 calories consumed when he was in Beijing was probably a little different than when he was in London. When he's done swimming casually in retirement, how he burns calories will be different then when he was training 6 days a week. When he's 35 it'll change even more. When he's 50, as the body changes like those factors mentioned above change with age, it'll be different yet and still. There is no definitive answer on how the body efficiently will burn a set # of calories at any one given time.

Still not answering the right question.

Quote from Iaaaiws : Still not answering the right question.

Am I? Or is the answer not inferred enough from my response?

The answer is always going to be theoretical using a best guess.
Efficiency is usually statistical.
Statistics require input.
The input will vary.
The input will be based on the situation at hand.
That guess will be made after putting it all together and finding out a result.